Fuel injector



Oct. 8, 19 3 Filed Feb( 13, 1961 A. G. M CORMICK FUEL INJECTOR FIG. I

2 Sheets-Sheet 1 IN VENTOR.

ALAN G. MCCORMICK HIS TTORNEY Oct. 8, 1963 Filed Feb. 13, 1961 O In A. G. M CORMICK FUEL INJECTOR 2 Sheets-Sheet 2 FIG. 2

INVENTOR.

ALAN G. MCCORMICK www HIS ATTORNEY United States Patent Office 3 ,l 05, l 54 Patented Oct. 8, 1963 3,106,164 FUEL INJECTOR Alan G. McCormick, 1408 Laird Ave, Salt Lake City, Utah Filed Feb. 13, 1961, Ser. No. 88,697 4 Claims. (Cl. 10338) The present invention relates to pump mechanisms and, more particularly, to a new and improved pump mechanism, particularly useful as a fuel injector, which will exhibit a high degree of reliability, even for operation at high pressures, and which will not require the close machining tolerances of pumps heretodore used.

In the past there have been many attempts to devise suitable fuel injection pumps to replace the conventionally used carburetor mechanisms of internal combustion engines. Carburization mechanisms of presently known and used types are universally recognized as being very inefficient. And yet, no suitable substitute therefor in the form of a fuel injection system has been able to be devised without complex mechanisms and attendant prohibitive cost thereof as a result of the extremely close tolerances which must be kept during the machining of the parts, in order to accommodate the pressure ranges necessitated for prop-er operation. The fuel injection pumps heretofore used commonly employ a plunger working in a cylinder, which plunger is intermittently actuated to deliver measured quantities of fuel to the engine associated therewith. Such a simple type of plunger cylinder arangement requires a leakproof fit with tolerances as small as threeto fivemillionths of an inch, particularly when using light fuel such as gasoline having little or no lubricating properties.

Such close tolerances are required even in the case of bellows pumps which have been devised, where the gasoline or other fuel enters the bellows cavity and the bellows is driven mechanically.

Accordingly, it is an object of the present invention to provide a new and improved bellows pump which isolates the plunger cylinder or barrel construction from the fuel being pumped, and wherein the bellows thereof is actuated by a closed hydraulic system.

A further object of the invention is to operate a fuel injector pump hydraulically and to isolate the hydraulic system from the fuel path so as to reduce wear of moving parts and also to adapt the system to use of O-ring seals for providing leak-proof structure.

A further object of the invention is to provide a novel fuel injector having a unique bellows design wherein a low Working pressure at the plunger thereof can produce extremely high pressures at the fuel outlet of the pump.

According to the present invention the pump includes a plunger working in the bore of a barrel, the bore communicating with a thin metallic bellows affixed to the end of the barrel. A suitable quantity of hydraulic fluid is included within the bore (which may be replenished for any slight leakage present). A cylinder is secured to the barrel and encloses the aforementioned bellows member so as to form a space between the bellows and the cylinder to constitute a fuel receiving chamber. Inlet and outlet ports of the fuel system communicate with this fuel chamber so that upstrokes of the plunger of the system will draw fuel into the chamber whereas down strokes will expand the bellows so as to produce an outstream of fuel under exceedingly high pressure, when desired. The plunger of the system may simply be provided with an O-ring so that the plunger, operating at 40 lbs. pressure at its O-ring seal will produce an outstream of fuel in the 10004500 lbs. pressure range. The system may be devised for even higher output pressures by increasing bellows size, and this with. use of but an O-ring seal at the barrel plunger bore. Thus, machining tolerances can be kept at reasonable limits (e.g. five-thousandths of an inch) at the barrel-plunger bore.

As will be seen, the pump or fuel injector may be operated as a single unit, or multiple injectors may be included in a radial 0r inline casing to supply a plurality of fuel outstreams which are appropriately synchronized.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the acornpanying drawings in Which! FIGURE 1 is a vertical section of a pump or fuel injector according to the invention.

FIGURE 2 is a vertical section of a unit incorporating a plurality of :fuel injectors connected in tandem and simultaneously controlled and progressively actuated.

FIGURE 3 is a section of a radial unit incorporating a plurality of fuel injectors of the invention, with the fuel injectors being progressively actuated by a single cam lobe.

In FIGURE 1 the casing 1b of the fuel injector is shown to rest upon support 11 and includes a casing cover 12 secured thereto by conventional attachments (not shown). Disposed interiorly of casing 10 is a plunger 13 which is provided with elongate portion 14. Barrel 15 is interiorly and sl-ideably disposed within casing 10 and is provided with a bore 16 delineated by a narrow, stroke portion 17 and an enlarged bore area 18. As is shown, the elongate portion 14 of plunger 13 is reciprocatingly disposed within stroke portion 17 of the bore 16.

Barrel 15 is threaded at 19 for threaded engagement with threaded portion 2% of cylinder 21. Barrel 15 is also threaded at 22 to receive the threads 23 of cap 24. Plunger 13 includes a flange 25 which overlaps the nut aperture 26 to engage nut 24 thereof and thus serve as a stop for plunger 13. Plunger 13 also includes a recessed area to accommodate washer 27. A plunger return spring 28 is disposed between washer 27 and shoulder 2? of easing lll. Washer 27 may be radially slit to accommodate its mounting to plunger 13. To accommodate hydraulic fluid loading plunger 13 may be supplied with an air bleeder aperture or bore A, with radial aperture A communicating therewith, and with set screw S (for the actuation of which screw driver admittance aperture A" is provided).

At this point it should be noted that, while for some design considerations bore area 13 should be enlarged over stroke portion 17, this need not necessarily be the case under all circumstances, particularly for small units.

A thin metallic bellows member 31 is welded, threaded, or otherwise secured to the end of barrel 15 at W. Welded to the remaining end of the bellows at W is a spring seat pin 32, forming an end extension of bellows 31. A bellows return spring 33 is disposed about pin 32 and engages the recess seat 34 provided in cylinder 21. A T-slot 35 is provided in the end of cylinder 21 to accommodate the flanged end 36 of bolt 37 which 36 is threaded or otherwise secured to or into the end of the latter.

For variable speed fuel injectors the apertures '38 will have to be elongated vertically, as shown, to admit fuel inlet and outlet conduit 39 and 40 to be threaded into ports 0 so as to be in communication with the fuel chamber 41 as is provided between bellows 31 and cylinder 21. In a similar manner the barrel 15 will be supplied with a vertically elongated aperture 42 for admitting hydraulic fluid conduit 43 or" the hydraulic fluid replenishing system (not shown) to be threaded into port O-rings 43 and 44 are optionally supplied in the position shown to preclude leakage where the pressure ranges utilized require the employment of such. In any event, it is desirous, generally essential for practical tolerances, that an O-ring 45 be supplied at the end of elongate portion 14 and plunger 13 so as to preclude leakage through the stroke portion 17 of barrel bore 16. (Rather than being elongated vertically, the apertures 38 and 42 may be otherwise enlarged so as to accommodate barrel, cylinder movement (15-21) as hereinafter described. Conduits 39, 40 and 43 will be of copper, generally, and be sufiiciently flexible for up-anddown adjustment of the barrel, cylinder combination 15 21.)

Finally, bolt 37 will be threaded into the threaded aperture 47 of easing Iii.

A suitable quantity of hydraulic fluid, which is admitted into the bore 16, is designated 49, and co-acts with the reciprocating plunger 13 in expanding bellows 31 downwardly against return spring 33.

Shaft 59 with cam lobe 51 are provided, and lobe 51 is positioned to contact the head 29 of plunger 13.

The structure of FIGURE 1 operates as follows. Barrel, cylinder combination *15-21 is slideable within casing 19. Thus, the rotation of bolt 37, which is a throttle adjustment means, will translate the barrel, cylinder combination 15, 21 upwardly or downwardly, depending upon the rotationof bolt 37. (For all positions, spring 28 forces plunger 13 against cam 51.) Thus, adjustment of bolt 37 serves to regulate the duration of contact of cam lobe 51 with plunger head 29. It will be seen with reference to FIGURE 1 that there is a slight space between the base of cylinder 21 and the seat therefor of casing 10. As shown in FIGURE 1 the device is adjusted for the contact of plunger 13 by cam lobe 51 for 360 of revolution of the lobe. Were the cylinder 21, barrel 15 combination lowered by the appropriate rotation of bolt 37, then the period of contact of lobe 51 with plunger 13 would be somewhat less than '3 60. In such an event the stroke of plunger 13 would be reduced, as would also its period of actuation by cam lobe 51. "This would result in a throttling down of the device. For maximum speed of the internal combustion engine supplied with the fuel injector of the invention, maximum plunger displacement and hence maximum contact of cam lobe 51 with plunger 15 would be required; thus, bolt 37 would be turned upwardly as necessary.

Spring 28 merely serves to return plunger '13 after its down stroke, thus keeping plunger 13 against the periphery of lobe 51 within the limits imposed by adjustment bolt 3'7. The hydraulic fluid employed 49 will be substantially non-compressible so that it will respond to the down and up strokes of plunger 13 in expanding bellows 31 downwardly against return spring 33 and, alternatively, pen,

mitting the same to contract under the pressure of return spring 33. Bore 16 thus constitutes a hydraulic fluid chamber which may either'be closed or, preferably, supplied with aperture 42 to provide admittance for conduit 43 of the hydraulic fluid replenishing system (not shown). Check valves are supplied conduit 43 (not shown) and conduit 39 and 40.

It has been prove-n by experiment that the provision of an O-ring seal 45 about annular recess 53 of plunger 13 operates very satisfactorily for producing extremely high pressures on the fuel being pumped through the injector. Thus, the displacement of hydraulic fluid 49 produced by the d'ownstnokes of plunger I3 will expand bellows 31 downwardly land outwardly so as, in effect, to multiply the pressure exerted on the hydraulic fluid by plunger 13 an enormous amount, so that the fuel in fuel chamber 41 will be sent through fuel outlet conduit nozzle 40 at a high pressure. The upstroke of plunger 13 will permit the bellows 31 to contract, thereby creating reduced pressure within it'uel chamber 41 so as to permit the check valve of conduit 40 to close and the check valve of conduit 39 to open.

The several fuel injectors PI of the structure of F1"- URE 2 are identical to that of FIGURE 1, with however a multiple recess casing ltl being supplied and being provided with a casing cover 12'. Shaft 56 this time is supplied with a plurality of Ilobes 51 which are progressively off-set in the usual manner to contact in quadrature relationship the several plunger-s 13 of the sevenal fuel injectors FI. Throttling adjustment bolts 37' are similar to their counterpart 37 in FIGURE 1 but additionally have a gear configured head 54 which engages rack 55. 'Ilhus, the translation of rack 55 to the right and left, as shown by arrow 56, will produce corresponding adjustment in height of the sevenal barrel and cylinder combinations so as to effect a thmottlting of the overall device. The structure of FIGURE 2 may be used with an internal combustion engine where the fuel injectors F1 are individually adjusted by adjustment screws 37 as is necessary so as to supply uniform streams of fuel.

For convenience of illustration in FIGURES 2 and 3 the hydraulic conduit 43 and fuel conduit 39 and 40 are not shown; likewise, the apertures therefor are not illustrated.

In FIGURE 3 a radial system is shown in fragmentary view incorponating, again, a plurality of fuel injectors FI which, where four are used, may be spaced apart and are sequentially engaged by cam 51 mounted to shaft 59. (For convenience, only two of four, quadrature mounted, fuel injectors F1 are shown in FIGURE 3.) In the case of the structune of FIGURE 3 it is believed that the same will be manufactured less expensively than the FIGURE 2 structure, since only one cam lobe 51 is needed to actuate all four of the fuel injectors F1. The block or casing 10 may comprise a ring having appropriate face plates secured thereto (not shown) and be radially bored (see bores B) and provided with threaded plugs P, as shown, for accommodation of the fuel injectors FI. Translation may be accomplished by rotation of circular rack CR shown in fragmentary view) which is in engagement vu'th bolts 37.

While four fuel injectors have been illustrated in FIG- URES 2 and 3, in actual practice any number may be incorporated in the structures shown.

While particular embodiments of the present invention have been shown and described, it will be obvious to those slcflled in the art that changes and modifications may be made without departing from this invention in its broader aspects, and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

I A fuel injector including, in combination, a barrel having a bore, a reciprocatory plunger disposed within said bore of said barrel, a bellows fixedly secured to said barrel and in communication with said bore, hydraulic fluid means contained in said barrel between said bellows and said plunger and responsive to the movement of said plunger for expanding said bellows in accordance there with, eccentric cam means for engaging said plunger to impart reciprocative motion thereto, a closed-end cylinder fixedly secured to said barrel and containing said bellows, said bellows being spaced from said cylinder to form a fuel chamber therebetween, said cylinder contaming inlet and outlet ports communicating with said fuel chamber, and means for adjusting the spacing between the barrel and cylinder combination and said eccentric cam means and, thereby, the disposition of said plunger relative to said eccentric cam means so as to vary the length and duration of the stroke of said plunger within said bore of said barrel.

2. A fuel injector including, in combination, a casing having a pair of enlarged, conduits admittance apertures, a barrel slidcably disposed within said casing and having a bore, a reciprocatory plunger disposed Within said bore of said barrel, a bellows fixedly secured to said barrel in communication with said bore, hydraulic fluid means contained in said barrel between said bellows and said plunger and responsive to the movement of said plunger for expanding said bellows in accordance therewith, means engaging said plunger for imparting reciprocative motion thereto, a cylinder slideably disposed within said casing, fixedly secured to said barrel and containing said bellows, said bellows being spaced from said cylinder to form a fuel chamber therebetween, said cylinder containing fuel inlet and outlet ports communicating with said fuel chamber, means for adjusting the disposition of the bar rel and cylinder combination relative to said casing, fuel inlet and outlet conduit respectively passing through said casing at said enlarged apertures and engaging said ports, said enlarged apertures accommodating barrel-cylinder disposition adjustment.

3, A fuel injector according to claim 2 wherein said disposition adjusting means comprises a bolt threaded into and through said casing and retentively engaging said cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 1,597,690 Moulet Aug. 31, 1926 2,301,407 Houser et al Nov. 10, 1942 2,559,364 Mashinter July 3, 1951 2,843,044 Mashinter July 15, 1958 2,843,045 Mashinter July 15, 1958 2,853,024- Bruce Sept. 23, 1958 2,856,857 Saalfrank Oct. 21, 1958 2,874,640 Vickers Feb. 24, 1959 2,894,459 McDuifie July 14, 1959 2,916,998 Miller Dec. 15, 1959 2,919,652 Fay Jan. 5, 1960 2,944,490 Pleuger et a1. July 12, 1960 2,980,024 Pope Apr. 18, 1961 

1. A FUEL INJECTOR INCLUDING, IN COMBINATION, A BARREL HAVING A BORE, A RECIPROCATORY PLUNGER DISPOSED WITHIN SAID BORE OF SAID BARREL, A BELLOWS FIXEDLY SECURED TO SAID BARREL AND IN COMMUNICATION WITH SAID BORE, HYDRAULIC FLUID MEANS CONTAINED IN SAID BARREL BETWEEN SAID BELLOWS AND SAID PLUNGER AND RESPONSIVE TO THE MOVEMENT OF SAID PLUNGER FOR EXPANDING SAID BELLOWS IN ACCORDANCE THEREWITH, ECCENTRIC CAM MEANS FOR ENGAGING SAID PLUNGER TO IMPART RECIPROCATIVE MOTION THERETO, A CLOSED-END CYLINDER FIXEDLY SECURED TO SAID BARREL AND CONTAINING SAID 